Conventional devices for cutting a bundle of fibers such as a strand or tow of inorganic fibers such as glass fiber have used a cutter roller which comprises a rotatable cylindrical body having a plurality of radial grooves formed in the outer periphery of the cylindrical body and extending longitudinally along the cylindrical body, and relatively thin plate-like cutter blades each being mounted in a respective groove. The cutter roller is disposed with respect to an elastic roller, having an elastic member formed of urethane rubber or the like mounted about an outer periphery thereof, in such a manner that the axes of rotation of the two rollers are parallel to one another, and that the distal ends of the cutter blades mounted on the cutter roller slightly press against the surface of the elastic roller. During the rotation of the cutter roller, the bundle of fibers is passed between the area of contact between the cutter blades of the cutter roller and the elastic roller, so that the cutter blades and the elastic roller cooperate to cut the fiber bundle, thus producing cut fibrous materials of a length corresponding to the interval between the cutter blades.
However, in cutting devices of this type, the width of the mounting groove for receiving the cutter blade is intentionally designed to be large in order to provide a gap between the groove and the cutter blade. The blade is thus movable within this gap. Therefore, with such so-called rattling cutter blades, clogging of the cut material between the blades is less likely to occur, because the fibrous material jammed in between the cutter blades is discharged by the centrifugal force of the cutter roller. However, if this centrifugal force is not of a sufficient degree, the fibrous material may not be discharged, thus resulting in the fibrous material being clogged between the blades. To obtain a sufficient centrifugal force, the cutter roller must be rotated at high speeds, and for this reason the component parts of the cutter roller must be of a high precision. Further, the service life of the rattling cutter blade is shortened due to fatigue failure, and also the load on the machine body is increased, which may lead to a malfunction. Additionally, since the cut fibrous material is discharged from the space between the cutter blades at a high speed, the fiber bundle may become napped or loosen. This may adversely affect the quality of the product.
When it is intended to obtain fibrous material which is cut to a short length, the interval between the cutter blades is small, and therefore the cut fiber bundle is more likely to become jammed in between the cutter blades. Further, when cutting a thick bundle composed of an increased number of fibers, the fiber bundle is pushed deep into the space between the cutter blades during the cutting operation, and therefore the cut fiber bundles accumulate up to the distal ends of the cutter blades. An imperfect cutting by the cutter blade may then be encountered.
Various proposals have been made for preventing the clogging of the cutter by such cut fiber bundles. For example, as disclosed in Japanese Patent Unexamined Publication No. Sho. 55-42220, a wire is extended between cutter blades, and the cutter blade is brought into contact with a rubber roller for effecting the cutting. When the contact between the cutter blade and the rubber roller is released, the cut piece is discharged due to the resiliency of the wire. However, the fiber bundle is pressed against the rubber roller by the wire, and therefore in a direct cutting operation in which a glass fiber strand is formed by spinning and cut immediately after the sizing, a bundle of fibers in a wet condition will be pressed by the wire and may be deformed, and further the cut fiber bundle may adhere to the surface of the rubber roller. This results in several disadvantages such as the deformation of the fiber bundle when the adhered bundle is separated from the rubber roller, a nap may be created due to dispersion, or the generation of short fibers due to a re-cutting of the cut fiber bundle. Further as is disclosed in U.S. Pat. No. 4063479, a bar is provided between the cutter blades of a cutting device, and the bar is moved inwardly and outwardly between the cutter blades by partially deforming an elastic ring molded of an elastic material such as polyethylene elastomer, so that the cut piece is discharged exteriorly due to the restoring force of the deformed elastic material. This device also has similar shortcomings as with the previous device. Also, time and labor are required to assemble this device for pushing the cut fiber bundle out of the space between the cutter blades.
Therefore, there is clearly a need for a cutting device which is capable of readily discharging the cut fibrous material from between the cutting blades.